﻿// The MIT License (MIT)
// 
// Copyright (c) 2015-2018 Rasmus Mikkelsen
// Copyright (c) 2015-2018 eBay Software Foundation
// https://github.com/eventflow/EventFlow
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy of
// this software and associated documentation files (the "Software"), to deal in
// the Software without restriction, including without limitation the rights to
// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
// the Software, and to permit persons to whom the Software is furnished to do so,
// subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

using System;
using System.Collections.Generic;
using System.Linq;
using EventFlow.Extensions;
using EventFlow.Specifications;

namespace EventFlow.Provided.Specifications
{
    public class AtLeastSpecification<T> : Specification<T>
    {
        private readonly int _requiredSpecifications;
        private readonly IReadOnlyList<ISpecification<T>> _specifications;

        public AtLeastSpecification(
            int requiredSpecifications,
            IEnumerable<ISpecification<T>> specifications)
        {
            var specificationList = (specifications ?? Enumerable.Empty<ISpecification<T>>()).ToList();

            if (requiredSpecifications <= 0)
                throw new ArgumentOutOfRangeException(nameof(requiredSpecifications));
            if (!specificationList.Any())
                throw new ArgumentException("Please provide some specifications", nameof(specifications));
            if (requiredSpecifications > specificationList.Count)
                throw new ArgumentOutOfRangeException($"You required '{requiredSpecifications}' to be met, but only '{specificationList.Count}' was supplied");

            _requiredSpecifications = requiredSpecifications;
            _specifications = specificationList;
        }

        protected override IEnumerable<string> IsNotSatisfiedBecause(T obj)
        {
            var notStatisfiedReasons = _specifications
                .Select(s => new
                    {
                        Specification = s,
                        WhyIsNotStatisfied = s.WhyIsNotSatisfiedBy(obj).ToList()
                    })
                .Where(a => a.WhyIsNotStatisfied.Any())
                .Select(a => $"{a.Specification.GetType().PrettyPrint()}: {string.Join(", ", a.WhyIsNotStatisfied)}")
                .ToList();

            return (_specifications.Count - notStatisfiedReasons.Count) >= _requiredSpecifications
                ? Enumerable.Empty<string>()
                : notStatisfiedReasons;
        }
    }
}